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Index Color: The Fastest Proof-to-Print System?

(February 2008) posted on Wed Feb 06, 2008

Index separations are often avoided by those who fear being stuck with too many colors to print. This month, Trimingham debunks some myths about index color and explains how to use it as an effective tool in prepress.

click an image below to view slideshow

By Thomas Trimingham

To properly view and output this file I had to change all of the outline colors in the bitmaps to the closest Pantone matches. For the underbase file I made sure it was underneath all of the other files, and I set the outline color to transparent white and to overprint (this is a great Corel X3 option). The design was now ready for customization.

This wolf was a snap to personalize with a location right below the type (Figure 5). Other designs could have far more elaborate overlapping type and vector elements on top of the graphic. The important thing to remember is to create an underbase copy that is set to overprint in CorelDRAW or a separate underbase file in Illustrator of all vector elements. This way the underbase will not miss the type and other additions. I moved all of the separations in Figure 6 to show how they work together to build the image.

A properly separated index separation isn’t that much different from a checkerboard in the way that the squares fit together and one color stacks right inside another to create a third color. If the dots were small enough, they might have even blended so that no dots would be apparent to the casual viewer. Were this file to be output on a color printer, it would be very close in appearance to the screenprinted piece. Best of all, after the customer approves the proof, you can just hit the print key and output your films.


Impress with index

There are many benefits to using an index separation and proofing system in the same file. The greatest benefit is certainly speed. The file prints very easily, the printer proofs are very close to the final print, typographic changes are a snap, and the separations tend to be very fast. Depending on how it is done, the index print can look better than a traditional print, or it can be completely grainy without a lot of tonal range.


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